13.1 Histogram

Histogram is a a distribution of tones at the microphoto. In physical representation it is a graphic which shows brightness values on the horizontal axis and the amount of pixels having this values on the vertical axis. 

Tasks and possibilities 

In Altami Studio 3.1.0 application histogram is necessary by work with photos and white balance adjustment when you work directly with camera. 

With the help of the histogram you can assess and edit the photo on brightness (color saturation) and contrast. 

Calling the panel 

Calling of the histogram can be carried out through the menu View→Panels→Histogram, or by clicking with the right button of the mouse at the application panel and selecting in the appeared list the Histogram item.  

Description of the panel 

You can work with the histogram moving the transformation line, and using Brightness and Contrast sliders at the histogram panel. Both methods are replaceable, they duplicate each other. You can notice how by raising the Brightness value the transformation line moves in parallel to the original position up. By decreasing the value — down. Upon raising the Contrast value, there happens a turn of transformation line counterclockwise, by decreasing — clockwise. 

Values on Brightness and Contrast scales range from 0 to 255 units. The brightness value in a zero means the image which is not bright, black color; in 255 bright image, white color. The contrast parameter in a zero means a gray image, with low contrast; 255 parameter defines great loss of the details but the great contrast by which light and shadow are cut. 

Histogram can indicate amount of colors in all channels — red, blue, green, — and in each channel separately. If there is little color, then it is dark, if much, then — light. For displaying a special component you can press the button Turn on the component visualization. If you want to display the brightness of pixels, turn on the Turn on the Brightness component visualization button. 

On the vertical axis values of pixels amounts in respect to the maximum are displayed. The histogram can be not illustrative enough if it has too high brightness peaks in comparison with general values of pixels amount. In that case you can logarithmate the value of pixels amount. In order to do that, press the button Turn on the logarithmic mode of the histogram.  

*receiving inversion of colors (image negative) can be achieved only by moving the ends of transformation line or by using the negative filter.